Hot-air furnace.



No. 863,361. PATENTED AUG. 13, 1907. G. W. CRAWFORD.

HOT AIR FURNACE.

APPLICATION FILED Nov.1, 190s.

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GEORGE W. CRAWFORD, OF GROVE CITY,

PENNSYLVANIA.

HOT-AIR FRNACE.

Specification of Letters Patent.

Patented Aug. 13, 1907.

Application filed November l, 1906. Serial No. 341,590.

To all 'whom it may concern:

Be it known that I, GEORGE W. CRAWFORD, a citizen of the United States of America, residing at Grove City, in the county of Mercer and State of Pennsyl- Vania, have invented certain new and useful Improvemonts in Hot-Air Furnaces, of which the following is a specification, reference being had therein to the accompanying drawing.

This invention relates to certain new and useful improvements in furnaces, and the invention has for its object to provide an attachment for furnaces, which will insure a more positive heating of the cold air passing through a furnace casing.

My invention aims to provide a novel form of partition or grating adapted to be placed in a horizontal position directly above the combustion chamber or heating chamber of a furnace, whereby it will be necessary for all cold air admitted to the furnace casing to pass therethrough in order to reach the radiator, and the hot air distributing iues. I have found by experience that the cold air admitted t0 the lower part of the furnace casing has a tendency to travel upwardly in close proximity to the inner sides of the same, and escape through the distributing Rues without being materially heated either by the combustion chamber or radiator of the furnace. This is especially true in windy weather', and causes considerable discomfort in the compartments heated by the furnace. By adapting my improved attachment to furnaces it will be impossible for any air to escape to the top of the furnace casing without first passing through the partition, and as the partition is maintained in a cherry-red or heated state, the air passing therethrough will be thoroughly heated.

The detailed construction entering into my improved furnace attachment will be presently described and then specifically pointed out in the appended claims.

Referring to the drawing forming part of this speciication, like numerals of reference designate corre'- sponding parts throughout the several views, in which:

Figure l is a vertical view partly in section of a conventional form of furnace equipped with my improved attachment, Fig. 2 is a vertical sectional view of one form of the improved attachment, Fig. 3 is an elevation of the same, Fig. 4 is a vertical sectional view of a modified form of the improved attachment, and Fig. 5 is an elevation of the same.

In the accompanying drawing, I have illustrated an ordinary furnace consisting of an outer casing 1 having a cold air inlet pipe 2 near its base, and hot distributing flues 3 in its deflector top 4. The top 4 is made separate from the casing I and is connected thereto by a ring or annulus 5. The casing 1 contains an ash pit 6, a fire box or combustion chamber 7', and a detachable radiator 8, said radiator having an exhaust iue 9. Extending above the upper sides of 4 the combustion chamber 7 is a fiat spacer member 16, and depending from the radiator 8 is a contracted i flue 17 providing communication between the radiator and the combustion chamber at the spacer' I6.

My invention resides in a horizontal perforated partition 10 disposed between the combustion chamber 7 and the radiator S, said partition being preferably in the form of a grate or screen, and bearing against the inner wall of the casing and beneath the annulus 5 and bearing centrally upon the spacer member 16, and provided with a central opening l5 and bearing around the connecting flue 17. By this means the grating is firmly held in position, the annulus preventing any upward movement and the spacer member preventing any downward movement.

As shown, the member l0 is located parallel with and in juxtaposition to the lower surface of the radiator 8, the latter serving to maintain the outer portion of the member 10 in a heated condition, an essential feature in order to produce the result intended, namely, the provision of an auxiliary heating member through which all of the air must pass in its passage through the furnace. The member l0 is heated by the opposing surfaces of the combustion chamber and radiator by radiation and by the contacting portions of the member and the spacer and top of the combustion chamber by conduction. As the contact is made at substantially the hottest portion of the furnacethe point of exit of the heat from the combustion chamber-it will be readily understood that the surrounding wall of the member l0 will be kept at an exceedingly high temperature, which will be communicated, by conduction, to the remaining portions of the member. As, however, the colder air is located along the walls 1 of the furnace, and therefore is brought in contact with the outer portion of the member 10, a point where the heat produced by conduction is of less temperature, such air wouldl not receive as high a preliminary heating. This result is, however, overcome by the locating of the member in juxtaposition to the bottom of the radiator and parallel therewith, as above described.

lIn Figs. 2 and 8, I have illustrated a grate ll as formed of a single piece of material, while in Figs. 4 and 5, I have shown a modified form of partition consisting of a heavy woven wire screen l2 having metallic bound edges lll. This screen can be readily used in lieu of the grate 11.

In the construction of either the preferred or modified form of partition, a central opening l5 is provided whereby the radiator can be connected to the chamber 7 or vice versa. The heat thrown off by the combustion chamber 7 is adapted to maintain the partition l0 in a hot condition, whereby all air passing through the same will be thoroughly heated before escaping into the Hues 3.

My improved attachment is applicable to various types of furnaces employed for heating air, and for this reason, I do not care to coniine myself to the size, proportion, material, or minor details ot construction, as such changes as are permissible by the appended claims7 may be resorted to without departing from the spirit and scope of the invention.

What I claim and desire to secure by Letters Patent, is:-

l.In a hot air furnace the combination with an outer casing', a combustion chamber' disposed within said casing, a radiator' disposed within said casingand spaced from said chamber' and connected thereto by a contracted central ilue, and an auxiliary heating member' bearing, against the inner' walls ot the casing and provided with a central aperture bearinbr around said connecting ilue between the chamber' and radiator, said member extending in a direc tion parallel with and in juxtaposition to the lower surface of the radiator'.

2. In a hot air furnace, the combination with an outer casing, a combustion chamber disposed within said casing and provided with a spacer member upon its upper side, a radiator disposed within said casing and spaced from said chamber and connected thereto by a contracted centrai flue at the spacer member, and an auxiliary air-heating member bearing against the inner walls of the casing and upon said spacer' member and provided with a central aperture bearing around said connecting nue between the chamber and radiator, said member extending in a direction parallel with and in juxtaposition to the lower surfa'cetot' the radiator.

3. In a hot air furnacey a casing formed in two portions connected by an inner annulus, a combustion chamber disposed within said casing and provided with a spacer member upon its upper' side, a radiator disposed within said casing and provided with a vcentral flue connecting the same to the combustion chamber at the spacer member, said radiator having its lower surface extending in a horizontal plane, and an auxiliary air-heating member parallel with and in juxtaposition to the bottom of said radiator'. said member' bearing, against the inner wall of the casing and beneath said annulus and bearing; centrally upon said spacer' member and with a central aperture bearing around said flue.

In testimony whereof I aiix my signature in the pres ence of two witnesses.

GEORGE W. CRAWFORD.

Witnesses E'r'rii CRAWFORD, P. H. FIRM. 

